In California, children from low-income households are nearly three times more likely to be obese as children from affluent households, according to a report published by UCLA researchers recently. Statewide, 21 percent of teens living in low-income families are obese, researchers said, compared to eight percent of teens from more affluent families.

"Low-income" was defined as having an income of less than $19,971 for a family of four or $12,755 for a family of two, according to federal poverty guidelines, while "more affluent" was defined making more than $59,913 for a family of four or $38,256 for a family of two, researchers said.

There are about 480,000 obese adolescents from all income levels in California, according to the report. The researchers blamed the disparity in obesity on a higher intake of sugary soda and fast food, fewer opportunities to participate in organized sports, more television watched, and less general physical activity. High numbers of fast-food restaurants and low numbers of parks in poorer neighborhoods contribute to the problem, they said.

"Our neighborhoods are literally making us fat," said Susan H. Babey, one of the policy brief's authors.

"We need better strategies and more thoughtful urban planning if we're going to make our towns and cities livable, not just places where we live."

When surveyed, between 46 and 49 percent of low-income teens reported eating fast food on the previous day, compared to 37 percent of more affluent teens. In addition, 56 percent of low-income teens reported watching more than two hours of television per day, compared to 46 percent of more affluent teens. The report's authors called on city planners to get behind zoning ordinances that would regulate the number of fast-food restaurants while offering incentives for grocery stores that stock fresh fruits and vegetables.

In July, the Los Angeles City Council approved a one-year moratorium on the opening of fast-food restaurants in a 32-square-mile portion of the city encompassing the South Los Angeles area.